Conventionally, there has been known a substrate processing system that performs a substrate process, such as a liquid process with a processing liquid or a gas process with a processing gas, to a substrate such as a semiconductor wafer, or the like.
By way of example, a substrate processing system described in Patent Document 1 includes multiple substrate processing units stacked in multiple stages, a substrate accommodating unit capable of accommodating multiple substrates loaded from the outside, two substrate transfer apparatuses stacked up and down to respectively correspond to an upper group and a lower group of the multiple substrate processing units and configured to unload substrates from the substrate accommodating unit and load the substrates into the substrate processing units, and a substrate delivery apparatus configured to deliver a substrate accommodated in the substrate accommodating unit to another position in the substrate accommodating unit.
In this substrate processing system, the substrates loaded from the outside are accommodated at an accommodation position in a lower portion within the substrate accommodating unit. Then, substrates, which are processed in the lower group of the substrate processing units, are unloaded by the substrate transfer apparatus corresponding to the lower group, and then, loaded into the lower group of the substrate processing units. Further, substrates, which are processed in the upper group of the substrate processing units, are delivered by the substrate delivery apparatus to an accommodation position in an upper portion within the substrate accommodating unit. Subsequently, the substrates are unloaded by the substrate transfer apparatus corresponding to the upper group, and then loaded into the upper group of the substrate processing units.
Further, the substrate processing system described in Patent Document 1 includes an inverting device configured to invert the front and rear surfaces of a substrate. A substrate accommodated in the substrate accommodating unit is unloaded by the substrate transfer apparatus and then loaded into the inverting device if necessary. Then, after the front and rear surfaces of the substrate are inverted in the inverting device, the substrate is loaded into the substrate processing unit.
Patent Document 1: Japanese Patent Publication No. 5000627
However, in the substrate processing system described in Patent Document 1, the substrate transfer apparatus transfers substrates to the substrate processing units and also transfers substrates from the substrate accommodating unit to the inverting device. As a result, a heavy load is applied to the substrate transfer apparatus. For this reason, it is difficult to increase the number of wafers to be transferred per unit time in the substrate processing system.
Further, such a problem may occur, not only in the inverting device, but in a case where the substrate transfer apparatus accesses another processing unit such as an inspection device.